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Showing 1 to 20 of 20 for “"Landau theory"”.
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Electronic instabilities and the Martensitic transition in A-15 compouns
… from two different standpoints. The first is a Landau theory based on Gorkov's physical model of a Peierls-like charge density wave (CDW) transition involving electronic CDW order parameters coupled to phonon coordinates. Pretransition elastic anomalies, softening of the [llOJ transverse ([110J …
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Advances in the modelling of in-situ powder diffraction data
… analyse the behaviour of structural parameters, Landau theory and its corresponding equations were used, owing to the fact that structural parameters (e.g. lattice strain, changes in atomic positions or occupancy) comprise an order parameter as defined in Landau theory. For description of the …
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Information Geometry For Nonlinear Least-Squares Data Fitting And Calculation Of The Superconducting Superheating Field
… of a bulk superconductor within the GinzburgLandau, which is valid only near Tc , and Eilenberger theory, which is valid at all temperatures. We calculate as functions of both the Ginzburg-Landau parameter [kappa] and reduced temperature t = T /Tc the superheating field Hsh and the critical …
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Measurements of the spontaneous polarization in KH(2)PO(2)
… of 1.87 uc/cm(2) at the transition. Laudau theory allows separate calculation at specific heat contributions of the lattice and polarization and thus the total specific heat, which agrees very well with direct calorimetric determinations, although the decomposition differs from that …
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Heat capacity of dilute solutions of liquid He[superscript 3] in He[superscript 4] at low temperatures
… concentration can be explained in, terms of the Landau theory of a Fermi liquid. The perturbation method, which Bardeen, Baym j and Pines used to determine an,effective potential v(q) between He 3 quasiparticles from later data on the magnetic properties of these solutions, was used to estimate …
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A study of vortex lattices and pulsar glitches
… the phenomenon of superconductivity: The London theory, the Ginzburg-Landau theory and the BCS theory. We review works by several authors who utilized these theories as the basis for their investigation. In our literature review we study the behavior of single and multivortex states in mesoscopic …
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Many-body physics and non-equilibrium dynamics in ultracold atomic systems
… optical lattice. Finally I apply a Ginzurg-Landau theory to model experimental studies of superfluid 3He embedded in nematically ordered aerogel, finding evidence for a new phase of matter --the ``polar phase"-- which is not seen in bulk 3He.
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Dynamical pairing states in cold gases
… kinetic equation and time-dependent Ginzburg-Landau theory are not applicable. 'The nonequilibrium dynamics can be explored in cold Fermi gas at a Feshbach resonance, a system with magnetically tunable interaction. Motivated by recent experiments, in Chapters 2 and 3 we study the pairing of …
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Quasi-one-dimensional magnetism in TiOCl and a theory of a lightly doped dimerized insulator
… for the failure of conventional mean-field theory to describe the details of the transition such as its first order character. It will be shown that a simple Ginzburg-Landau theory which takes proper account of interchain-frustration is capable of explaining this unconventional behavior.
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A study of holographic superconductors
… systems can be described by a gravitational theory within the frame work of gauge/gravity correspondence is investigated more extensively for s-wave superconductors. We consider a gravitational theory with a black hole solution in anti de Sitter spacetime, coupled to an Abelian-Higgs system …
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Landau Model for Films and Interfaces of Superfluid Helium-4 at T = 0k
We use a Landau theory appropriate to an inhomogeneous superfluid at temperature T = 0 to describe structural and dynamical effects at a gas/superfluid interface and for a superfluid film on an inert attractive substrate. The parameters of the theory are determined phenomenologically by fitting …
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Landau model for films and interfaces of superfluid 4HE at T=OK
We use a Landau theory appropriate to an inhomogeneous superfluid at temperature T = 0 to describe structural and dynamical effects at a gas/superfluid interface and for a superfluid film on an inert attractive substrate. The parameters of the theory are determined phenomenologically by fitting …
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Propagation of zero sound in liquid He3
… results of the measurements are predicted by the Landau theory of a Fermi liquid, the velocity change and the temperature dependence of the attenuation coefficient at low temperatures being explained by the propagation of a new mode of sound, called zero sound. The velocity change is in …
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Probing the topology in band insulators
… Unlike phases described by the traditional Landau theory of symmetry breaking, the topological phases do not break symmetry, and it is not obvious in which measurable quantity will the topological index manifest itself. In this thesis, our main goal is to understand how topological …
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Computational Modeling of Superconductivity from the Set of Time-Dependent Ginzburg-Landau Equations for Advancements in Theory and Applications
… Using the set of time-dependent Ginzburg-Landau (TDGL) equations with inclusion of the interference current and the non-equilibrium phonon term, we modeled the dynamics of superconductors in various theory revealing states and practical purposes. A review of the history and phenomenon of …
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The Bogoliubov equations and their application to a normal-superconducting boundary
… discussion of the fourth example, the Ginzburg-Landau equations, for arbitrary electronic mean free path, are derived. In addition, the kernels of the Ginzburg-Landau theory are expressed in terms of the wave vector and frequency-dependent, normal conductivity. The Bogoliubov equations are then …
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Magnetism and superconductivity out of equilibrium: Towards ultrafast superconducting spintronics
… which we elucidate through the time-dependent Landau theory of phase transitions. On the other hand, the sub-nanosecond recovery time displays signs of a divergence as the critical temperature is approached that are indicative of a relaxation governed by anharmonic phonon decay. Subsequently, …
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Slave particle study of the strongly correlated electrons
… frameworks developed by Russian physicist Lev Landau: his theory of phase transition, and Fermi liquids. The Landau theory of phase transition and the Fermi liquid theory together, can successfully explain a wide range of phenomena from ferromagnetism and antiferromagnetism to the conventional …
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Statistical mechanics of the amorphous solid state of randomly crosslinked macromolecules
… state occurs. In this thesis a semi-microscopic theory of the vulcanization transition is developed, and the emergent amorphous solid state is studied in detail, close to the transition. In the first part of this work a derivation is presented of the free energy functional for a system of …
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Spatial-temporal patterns in evolutionary ecology and fluid turbulence
… for an appropriate long-wavelength effective theory. We report evidence of candidate long-wavelength collective modes in direct numerical simulations of the Navier-Stokes equations in a pipe geometry, where we uncover unexpected spatio-temporal patterns reminiscent of ecological predator-prey …